Intervention effect of Tuina pressing and kneading the Huantiao (GB30) acupoint on NF-κB p65 protein at spinal cord dorsal horn in sciatica rats / 中国骨伤

OBJECTIVE@#To observe the analgesic effect of Tuina by pressing and kneading the Huantiao (GB30) acupoint on rats with chronic constriction injury (CCI) and to explore the analgesic mechanism of Tuina on sciatica rats.@*METHODS@#Thirty-two SPF male SD rats weighing 180 to 220 g were randomly divided into fore groups:blank group (without any treatment), sham group (only exposed without sciatic nerve ligating), model group (sciatic nerve ligating) and Tuina group (manual intervention after lsciatic nerve ligating). The CCI model was prepared by ligating the right sciatic nerve of the rats, on the third day of modeling, the rats in the Tuina group were given pressing and kneading the Huantiao (GB30) point for 14 days, and the changes of paw withdrawal threshold(PWT), paw withdrawal latency(PWL) were measured before and on the 1st, 3rd, 7th, 10th, 14th and 17th days after modeling. The changes of sciatic functional index(SFI) were measured before and on the 1st and 17th day after modeling. The morphological changes of the sciatic nerve were observed by hematoxylin-eosin(HE) staining;and the differences in NF-κB protein expression in the right dorsal horn of the spinal cord of rats were detected.@*RESULTS@#Following modeling, there was no significant difference in PWT, PWL and SFI between the blank group and the sham group (P>0.05), but the PWT, PWL and SFI of the model group and the Tuina group decreased significantly (P<0.01). After manual intervention, the pain threshold of rats in Tuina group increased. On the 8th day of manual intervention (the 10th day after modeling), PWT in Tuina group increased significantly compared with that in model group (P<0.01). On the 5th day of manual intervention (the 7th day after modeling), the PWL of the massage group was significantly higher than that of the model group (P<0.01). The pain threshold of rats in Tuina group continued to rise with the continuous manipulation intervention. After 14 days of manipulative intervention, the sciatic nerve function index of rats in the Tuina group increased significantly(P<0.01). Compared with the blank group and sham group, the myelinated nerve fibers of sciatic nerve in the model group were disordered and the density of axons and myelin sheath was uneven. Compared with the model group, the nerve fibers of rats in the Tuina group were gradually continuous and the axons and myelin sheath were more uniform than those in the model group. Compared with the blank group and sham group, the expression of NF-κB protein in the right spinal dorsal horn of the model group was significantly increased(P<0.01). Compared with the model group, the expression of NF-κB protein in the right spinal dorsal horn of rats in Tuina group decreased significantly(P<0.01).@*CONCLUSION@#Pressing and kneading the Huantiao (GB30) point restores nerve fiber alignment;and improves the PWT、PWL and SFI in the CCI model by decreasing NF-κB p65 protein expression in the spinal dorsal horn. There fore, Tuina demmstrates an analgesic effect and improves the gait of rats with sciatica.

Exploring the effect of Tuina on the dendritic structure of spinal cord dorsal horn in rats with lumbar disc herniation based on NR2B/PSD-95 pathway / 针灸推拿医学（英文版）

Objective: To investigate the analgesic mechanism of Tuina (Chinese therapeutic massage) by observing the effect of the N-methyl-D-aspartate receptor subunit 2B (NR2B)/postsynaptic density-95 (PSD-95) pathway on the dendritic structure of spinal cord dorsal horn in rats with lumbar disc herniation. Methods: Fifty Sprague-Dawley rats were randomly divided into a blank group, a model group, a Tuina group, a blocker agent group, and a blocker agent + Tuina group. The sciatic nerve chronic constriction injury (CCI) model was prepared by the sciatic nerve ligation method. From the 4th day after modeling, rats in the Tuina group and the blocker agent + Tuina group were subject to daily Tuina intervention, and those in the blocker agent group and the blocker agent + Tuina group were daily intrathecally injected with NR2B blocker agent (MK-801). The spontaneous pain score was used to observe the pain behavior of all rats. The expression levels of NR2B and downstream PSD-95 were measured by immunohistochemistry, and the dendritic structure changes were observed by Golgi staining for rat spinal cord dorsal horn after 14 d of continuous intervention. Results: Compared with the blank group, the degree of rat spontaneous pain after CCI was elevated in both the model and the Tuina groups (P<0.01) and was reduced in the Tuina group after the Tuina intervention compared with the model group (P<0.05). Compared with the model group, the rat spontaneous pain level after blocking NR2B was reduced in both the blocker agent group and the blocker agent + Tuina group (P<0.05). The NR2B and PSD-95 protein levels were significantly higher in the model group compared with the blank group (P<0.01); the total number of dendritic branches was increased (P<0.01), and the total dendritic length became longer (P<0.01) in the spinal cord dorsal horn. The rat NR2B and PSD-95 protein levels were significantly decreased in the Tuina group compared with the model group (P<0.01); the total dendritic branch number was reduced (P<0.01) and the total length was shortened (P<0.01) in the spinal cord dorsal horn. After blocking NR2B, the expression levels of NR2B and downstream PSD-95 protein were significantly lower in both the blocker agent group and the blocker agent + Tuina group compared to the model group (P<0.01). The total branch number was significantly reduced (P<0.01), and the total length was significantly shortened (P<0.01) of the dendrites in the spinal cord dorsal horn. Conclusion: Tuina may exert an analgesic effect by remodeling the dendritic structure in the spinal cord dorsal horn in rats with lumbar disc herniation, and its mechanism may be related to the inhibition of NR2B/PSD-95 signaling pathway.

Chronic compression of the dorsal root ganglion activates the Wnt/β-catenin signaling pathway in the dorsal horn of the spinal cord in rats / 中华物理医学与康复杂志

Objective:To investigate the effect of chronic compression of the dorsal root ganglion (CCD) on the Wnt/β-catenin signaling pathways in the spinal dorsal horns of rats.Methods:Forty-two adult male Sprague-Dawley rats were randomly divided into a sham group ( n=9) and a CCD group ( n=33). The CCD group was subdivided into a 1d group ( n=6), a 3d group ( n=6), a 7d group ( n=9), a 14d group ( n=6), and a 28d group ( n=6) based on the post-operative time of the experiments. Before the operation for CCD and 1, 3, 5, 7, 14, 21 and 28 days afterward the mechanical withdrawal threshold was detected for all rats. Western blotting was conducted to detect the expression of active β-catenin and glial fibrillary acidic protein (GFAP) in the dorsal horn of the spinal cord 1, 3, 7, 14 and 28 days after the surgery. Seven days after the operation immunofluorescence was employed to detect the nuclear translocation of active β-catenin and the activation of astrocytes in the dorsal horn of the spinal cord. Results:The average mechanical withdrawal thresholds of the CCD groups were significantly lower than that of the sham group at each time point. The western blotting showed that the expression of active β-catenin in the CCD groups was significantly greater than in the sham group at each time point. Seven days after compression the expression of GFAP in the rats′ dorsal horns was significantly higher than in the sham group. Immunofluorescence indicated nuclear translocation of active β-catenin and the activation of astrocytes in the dorsal horn.Conclusion:The Wnt/β-catenin signaling pathways are significantly activated in the dorsal horn of the spinal cord after CCD, at least in rats. It may play an important role in the development of neuropathic pain.

Effect of electroacupuncture and pretreatment of electroacupuncture on pain sensitization and expression of P2X7R in spinal dorsal horn in rats with diabetic neuropathic pain / 中国针灸

OBJECTIVE@#To observe the occurrence time of neuralgia and the expression of purinergic ligand-gated ion channel 7 receptor (P2X7R) in the dorsal horn of the spinal cord after intraperitoneal injection of streptozotocin (STZ) in diabetic rats, and to explore the effect of electroacupuncture (EA) and pretreatment of EA on the heat pain threshold and expression of P2X7R in the spinal dorsal horn in rats with diabetic neuropathic pain (DNP), and to explore the possible mechanism of EA for DNP.@*METHODS@#PartⅠ: Thirty male SD rats were randomly selected from 64 male SD rats as the control group; the remaining rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model, and 30 rats were successfully modeled as the model group. The control group and the model group were divided into three subgroups respectively at 7, 14 and 21 days, with 10 rats in each subgroup. Body mass, fasting blood glucose (FBG) and thermal pain threshold were recorded at 7, 14 and 21 days after injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot. PartⅡ: Eight SD rats were randomly selected from 35 male SD rats as the blank group, and the remaining 27 rats were given intraperitoneal injection of STZ (10 mg/mL) at a dose of 65 mg/kg to establish the diabetes model. The 24 rats with successful diabetes model were randomly divided into a DNP group, an EA group and a pre-EA group, 8 rats in each group. Fifteen to 21 days after STZ injection, the EA group received EA at "Zusanli" (ST 36) and "Kunlun" (BL 60), continuous wave, frequency of 2 Hz, 30 min each time, once a day; the intervention method in the pre-EA group was the same as that in the EA group. The intervention time was 8 to 14 days after STZ injection. The body mass, FBG and thermal pain threshold were recorded before STZ injection and 7, 14 and 21 days after STZ injection; the expression of P2X7R in spinal dorsal horn was detected by Western blot 21 days after injection.@*RESULTS@#PartⅠ: Compared with the control group, in the model group, the body mass was decreased and FBG was increased 7, 14 and 21 days after STZ injection (P<0.01), and the thermal pain threshold was decreased 14 and 21 days after STZ injection (P<0.05), and the expression of P2X7R in spinal dorsal horn was increased 7, 14 and 21 days after STZ injection (P<0.05, P<0.01). PartⅡ: Compared with the blank group, in the DNP group, the body mass was decreased and fasting blood glucose were increased 7, 14 and 21 days after STZ injection (P<0.01). Compared with the DNP group, in the pre-EA group, the heat pain threshold was increased 14 and 21 days after STZ injection (P<0.05), while in the EA group, the heat pain threshold was increased 21 days after STZ injection (P<0.01), and the expression of P2X7R in the dorsal horn in the EA group and the pre-EA group was decreased (P<0.01).@*CONCLUSION@#The diabetic neuropathic pain is observed 14 days after STZ injection. EA could not only treat but also prevent the occurrence of DNP, and its mechanism may be related to down-regulation of P2X7R expression in the dorsal horn of the spinal cord.

Mechanism of Chuanxiong Rhizoma intervention on central sensitization of Panx1-Src-NMDAR-2B signaling pathway in neuropathic pain model rats / 中国中药杂志

Excitatory toxicity(ET) is an important factor of neuropathic pain(NPP) induced by central sensitization(CS), and the association of pannexin-1(Panx1)-Src-N-methyl-D-aspartate receptor subunit 2 B(NMDAR-2 B) is an important new pathway for ET to initiate CS. The present study confirmed whether the central analgesic effect of Chuanxiong Rhizoma extract(CRE) was achieved through the synchronous regulation of the brain and spinal pathways of Panx1-Src-NMDAR-2 B. In this study, dynamic and simulta-neo-us microdialysis of the brain and spinal cord in vivo combined with behavioristics, high performance liquid chromatography(HPLC)-fluorescence detection, microdialysis analysis(ISCUS~(flex)), ultrasensitive multifactorial electrochemiluminescence immunoassay, ELISA, and Western blot was employed to investigate the protein expression of NMDAR-2 B, Src, and Panx1, extracellular excitatory amino acids, cytokines, energy metabolites, and substance P in spinal dorsal horn(SDH) and anterior cingulate cortex(ACC) after CRE intervention with the rat model of spared sciatic nerve injury(SNI) as the experimental tool. Compared with the sham group, the SNI group exhibited diminished mechanical withdrawal threshold(MWT)(P<0.01), increased cold spray scores(P<0.01), glutamate(Glu), D-serine(D-Ser), and glycine(Gly) in extracellular fluids of ACC, and Glu, D-Ser, interleukin-1β(IL-1β), and lactic acid(Lac) in extracellular fluids of SDH(P<0.05), dwindled tumor necrosis factor(TNF-α)(P<0.05), and elevated protein levels of NMDAR-2 B, Src, and Panx1 in ACC(P<0.05). Compared with the SNI model rats, high-and medium-dose CRE(CRE-H/M) could potentiate the analgesic activity as revealed by the MWT test(P<0.05) and CRE-M enabled the decrease in cold spray scores(P<0.05). CRE-H/M could inhibit the levels of Glu, D-Ser and Gly in the extracellular fluids of ACC(P<0.05), and the levels of Glu in the extracellular fluids of SDH(P<0.05) in SNI rats. CRE-M significantly increased the levels of glucose(Gluc), Lac, interferon-gamma(IFN-γ), keratinocyte chemoattractant/human growth-regulated oncogenes(KC/GRO), and IL-4 in extracellular fluids of SDH in SNI rats(P<0.05). CRE-H/M/L could also inhibit the levels of NMDAR-2 B, Src and Panx1 in ACC and SDH in SNI rats(P<0.05). The central analgesic effect of CRE is presumedly related to the inhibited release of excitatory amino acid transmitters(Glu, D-Ser and Gly) in ACC and SDH of SNI rats, decreased protein expression of NMDAR-2 B, Src and Panx1 in the two regions, and the regulation of the Panx1-Src-NMDAR-2 B pathway in the spinal cord and brain. The above findings partially clarified the scientific basis of clinical analgesic effect of Chuanxiong Rhizoma.

Effect of wrist-ankle acupuncture on the expression of glutamate and NMDA receptor of the spinal dorsal horn in rats with neuropathic pain / 针刺研究

OBJECTIVE: To observe the effect of wrist-ankle acupuncture (WA) stimulation at "R4"- "R5" - "R6" on the expression of glutamate (Glu) and phosphorylated protein NMDAR1(p-NMDAR1) of the spinal dorsal horn in spared nerve injury (SNI) rats, so as to explore its mechanism underlying improvement of SNI. METHODS: A total of 36 SD rats were randomly divi-ded into sham operation, model and WA groups, with 12 rats in each group. The SNI procedure comprised an axotomy and ligation of the tibial and common peroneal nerves leaving the sural nerve intact. Rats of the WA group were treated by acupuncture at "R4"-"R5"-"R6" points from the 5th day to the 14th day after modeling. The mechanical pain thresholds were measured before and 5, 10 and 14 d after SNI, respectively. The cold allodynia was dectected by Acetone solution dropped onto the lateral plantar surface of the paw. Glu content and p-NMDAR1 expression of spinal dorsal horn were detected by 1H-MRS, ELISA and immunohistochemistry Methods. RESULTS: Compared with the sham operation group, the mechanical pain threshold of the model group was significantly decreased (P<0.01), the duration of cold stimulation foot contraction was increased (P<0.01), and the Glu content and p-NMDAR1 expression in the spinal dorsal horn were significantly increased (P<0.05, P<0.01). After WA intervention, the mechanical pain threshold was significantly increased (P<0.01), the duration of cold stimulation was significantly shortened (P<0.01), and Glu content and p-NMDAR1 protein expression of spinal dorsal horn were decreased significantly (P<0.05, P<0.01) in the WA group compared with the model group. CONCLUSION: WA can reduce pain sensitivity in rats with neuropathic pain, possibly by inhibiting the expression of Glu and p-NMDAR1 in the spinal dorsal horn.

Study on Mechanism of Analgesic Effect of 8-O-acetyl-safalinoside on Chronic Inflammatory Pain Model Rats / 中国药房

OBJECTIVE： To study the mechanism of analgesic effect of 8-O-acetyl-safalinoside （8-OaS） on chronic inflammatory pain model rats. METHODS ：Totally 30 male SD rats were divided into sham operation group （normal saline ）， model group （normal saline ），8-OaS low-dose ，medium-dose and high-dose groups （3，10，30 μg/kg），with 6 rats in each group. Except for sham operation group ，other groups were given planter injection of Freund ’s complete adjuvant to induce chronic inflammatory pain model. After successful modeling ，the rats in each group were given corresponding drugs intrathecally ，once a day，for 7 consecutive days. Then Von-Frey filaments were used to detect the planter pain threshold of the rats in each group ；the area under the planter pain threshold curve of each group and the half effective dose （ED50）of 8-OaS were calculated. Another 36 male SD rats were divided into sham operation group （normal saline ），model group （normal saline ）and 8-OaS group （dose of ED50），and the modeling method and administration route were the same as above. Immunofluorescence histochemical staining was used to observe the positive expression of ionized calcium binding adapter molecule 1（Iba-1）and signal molecule phosphorylated p38 mitogen-activated protein kinase （p-p38 MAPK）；Western blotting assay was used to determine the expression of Iba- 1，p-p38 MAPK，IL-1β，IL-6 and TNF-α in spinal dorsal horn of rats. RESULTS：Compared with sham operation group ，plantar pain threshold and area under the curve in model group were reduced significantly （P＜0.01）. Compared with model group ，plantar pain threshold increased significantly after 5，6，7 days of administration in 8-OaS low-dose group （P＜0.05），plantar pain threshold and area under the curve in 8-OaS medium-dose and high-dose groups were increased significantly （P＜0.05 or P＜0.01）. Most of above indexes in each dose group of 8-OaS were signifficantly different ，and ED 50 of 8-OaS was 18.87 μ g/kg. Results of immunohistochemistry staining and Western blotting showed that p-p 38 MAPK was mainly expressed in Iba- 1 positive cells. Compared with sham operation group ，the fluorescence density of Iba- 1 and p-p 38 MAPK in spinal dorsal horn ，the expression of Iba-1，p-p38 MAPK，IL-6，IL-1β and TNF-α were significantly increased in model group（P＜0.05 or P＜0.01）. Compared with model group ，the fluorescence density of Iba- 1 and p-p 38 MAPK in spinal dorsal horn ，the expression of Iba- 1，p-p38 MAPK， IL-6，IL-1β and TNF-α were decreased significantly in 8-OaS group （P＜0.05）. CONCLUSIONS ：Intrathecal administration of 8-OaS can effectively alleviate chronic inflammatory pain in rats. The mechanism may be related to the inhibition of the phosphorylation of p 38 MAPK and the expression of IL- 6，IL-1β and TNF-α.

Effect of sciatic nerve pulsed radiofrequency glial activation levels in spinal dorsal horn in chronic constriction injury rat models and its analgesia effect / 吉林大学学报(医学版)

Objective: To observe the effect of sea tic nerve pulsed radiofrequency (PRF) on the activation levels of microglia cells and astrocytes in spinal dorsal horn in the chronic constriction injury (CCD rat models, and to explore the relationships between the analgesic mechanism of sciatic nerve PRF and the activation levels of microglia cells and astrocytes in the spinal dorsal horn- Methods: Forty male SD rats were randomly divided into CCI shamoperation+RPF sham group (SS group). CC1 sham-operation + RPF group (SP group). CCI+RPF sham group (CS group). CCI+ RPF group (CP group) ( n 10). PRF was applied on the sciatic nerve on the 4th day after CC1 operation for 120 s, with a maximum temperature of 42"C. The mechanical withdrawal thresholds (MWT) and thermal paw withdrawal latencies 0. 05). Conclusion- PRF on sciatic nerve can relieve the neuropathic pain (NT) of the CCI rat models: PRF on saatic nerve can inhibit activation of the microglia cells in the spinal dorsal horn. The analgeac mechanism of PRF on sciatic nerve may be associated with the inhibition of the activation of microglia cells in the spinal dorsal horn.

Effects of intrathecal injection of M_ERK2-shRNA adenovirus on diabetic neuropathic pain in mouse / 解剖学报

Objective To explore the mechanism of extracellular regulated protein kinase 2 (ERK2) in diabetic neuropathic pain(DNP) mice. Methods Forty mice were randomly divided into four groups: control group, DNP group, siERK2-DNP group (intrathecal injection of M_ERK2-shRNA adenovirus), siRNA-DNP group (intrathecal injection of siRNA adenovirus). The pain threshold was detected after the model made successfully, the mechanical pain threshold was detected before moulding, after moulding 2 weeks, 4 weeks and 6 weeks. Spinal cord tissues were taken after 6 weeks, and the expression of ERK2 and nuclear factor ΚB (NFΚB) in the posterior horn of the spinal cord was detected by Western blotting and immunohistochemistry. Results Compared with the control group, the pain threshold of DNP group and siRNA-DNP group decreased significantly, the expression of ERK2 and NFKB increased significantly (P0. 05). Conclusion The marked down-regulation of ERK2 may be one of the important mechanisms affecting neuronal injury in the spinal dorsal horn of diabetic neuropathic pain.

Role of NL-1 in trafficking of GluR1-containing AMPA receptor to cell membrane in spinal cord dorsal horn during remifentanil-induced hyperalgesia in mice with incisional pain / 中华麻醉学杂志

Objective@#To evaluate the role of neuroligin 1 (NL-1) in trafficking of GluR1-containing AMPA receptor to cell membrane in spinal cord dorsal horns during remifentanil-induced hyperalgesia in mice with incisional pain.@*Methods@#Forty SPF healthy male C57BL/6J mice, aged 8-10 weeks, weighing 18-22 g, were divided into 5 groups (n=8 each) using a random number table method: control group (group C), NL1-shRNA plasmid group (group NL), incisional pain plus remifentanil group (group I+ R), incisional pain plus remifentanil plus blank vector group (group I+ R+ B), and incisional pain plus remifentanil plus NL-1-shRNA plasmid group (group I+ R+ NL). Negative lentivirus was intrathecally injected in group I+ R+ B.In NL and I+ R+ NL groups, 10 μl NL-1-shRNA lentivirus at 1×108 IFU/ml was intrathecally injected once a day for 3 consecutive days.Normal saline 10 μl was intrathecally injected at the same time point in C and I+ R groups.After transfection was stable, normal saline 0.1 ml was injected via the caudal vein for 4 consecutive times at 15 min intervals in C and NL groups.In I+ R, I+ R+ B and I+ R+ NL groups, 0.1 ml remifentanil 10 μg/kg was injected via the caudal vein for 4 consecutive times at 15 min intervals, and the model of incisional pain was established after the first administration.The mechanical paw withdrawal threshold (MWT) and tail-flick latency (TFL) were measured at 24 h before normal saline or remifentanil administration (T0) and at 3, 6, 24 and 48 h after the end of administration (T1-4). The animals were sacrificed after measurement of pain threshold at T4, and L4-6 segments of the spinal dorsal horn were then collected for determination of the expression of NL-1 protein and mRNA and AMPA receptors, and the ratio of AMPA receptor expression in the membrane protein to that in the total protein (m/t ratio) was calculated.@*Results@#Compared with group C, the MWT was significantly decreased, and TFL was shortened at T1-4, the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was up-regulated, and m/t ratio was increased in I+ R and I+ R+ B groups (P<0.05). Compared with I+ R and I+ R+ B groups, the MWT was significantly increased and TFL was prolonged at T1-4, the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was down-regulated, and m/t ratio was decreased in group I+ R+ NL (P<0.05).@*Conclusion@#NL-1 in spinal cord dorsal horns can promote the trafficking of GluR1-containing AMPA receptors to cell membrane, which is involved in the development and maintenance of remifentanil-induced hyperalgesia in mice with incisional pain.

Role of NL-1 in trafficking of GluR1-containing AMPA receptor to cell membrane in spinal cord dorsal horn during remifentanil-induced hyperalgesia in mice with incisional pain / 中华麻醉学杂志

Objective To evaluate the role of neuroligin 1 (NL-1) in trafficking of GluR1-containing AMPA receptor to cell membrane in spinal cord dorsal horns during remifentanil-induced hyperalgesia in mice with incisional pain.Methods Forty SPF healthy male C57BL/6J mice,aged 8-10 weeks,weighing 18-22 g,were divided into 5 groups (n=8 each) using a random number table method:control group (group C),NL1-shRNA plasmid group (group NL),incisional pain plus remifentanil group (group I+R),incisional pain plus remifentanil plus blank vector group (group I+R+B),and incisional pain plus remifentanil plus NL-1-shRNA plasmid group (group I+R+NL).Negative lentivirus was intrathecally injected in group I+R+B.In NL and I+R+NL groups,10 μl NL-1-shRNA lentivirus at 1×10s IFU/ml was intrathecally injected once a day for 3 consecutive days.Normal saline 10 μl was intrathecally injected at the same time point in C and I+R groups.After transfection was stable,normal saline 0.1 ml was injected via the caudal vein for 4 consecutive times at 15 min intervals in C and NL groups.In I+R,I+R+B and I+R+NL groups,0.1 ml remifentanil 10 μg/kg was injected via the caudal vein for 4 consecutive times at 15 min intervals,and the model of incisional pain was established after the first administration.The mechanical paw withdrawal threshold (MWT) and tail-flick latency (TFL) were measured at 24 h before normal saline or remifentanil administration (T0) and at 3,6,24 and 48 h after the end of administration (T1-4).The animals were sacrificed after measurement of pain threshold at T4,and L4-6 segments of the spinal dorsal horn were then collected for determination of the expression of NL-1 protein and mRNA and AMPA receptors,and the ratio of AMPA receptor expression in the membrane protein to that in the total protein (m/t ratio) was calculated.Results Compared with group C,the MWT was significantly decreased,and TFL was shortened at T1-4,the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was up-regulated,and m/t ratio was increased in I+R and I+R+B groups (P＜0.05).Compared with I+R and I+R+B groups,the MWT was significantly increased and TFL was prolonged at T1-4,the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was down-regulated,and m/t ratio was decreased in group I+R+NL (P＜0.05).Conclusion NL-1 in spinal cord dorsal horns can promote the trafficking of GluR1-containing AMPA receptors to cell membrane,which is involved in the development and maintenance of remifentanil-induced hyperalgesia in mice with incisional pain.

Expression of the NMDA receptor in the rat model of orchialgia / 中华男科学杂志

Objective@#To explore the expression of the N-methyl-D-aspartate (NMDA) receptor in the rat model of orchialgia and its possible mechanisms.@*METHODS@#According to Yoshioka's method, the male rats in the control group were injected with 0.2 ml saline, and those in the experimental group with 0.2 ml 2% acetic acid solution. Then we tested the behavioral responses of the rats and determined the expressions of the subunits NR1 and NR2B of the NMDA receptor in the dorsal root ganglion and spinal dorsal horn by Western blot, RT-qPCR and immunofluorescence staining.@*RESULTS@#The withdrawal latency was decreased in the model rats, reaching the lowest value at 4 hours after modeling, significantly lower than in the controls (［4.15 ± 0.84］ vs ［12.32 ± 1.05］, P 0.05).@*CONCLUSIONS@#The NMDA receptor plays an important role in pathogenesis of orchialgia in rats. In the early stage of pain, upregulating the expression of the subunit NR2B of the NMDA receptor can mediate peripheral hyperalgesia and consequently orchialgia.

Up-regulation of P2X7 Receptors Contributes to Spinal Microglial Activation and the Development of Pain Induced by BmK-I / 神经科学通报·英文版

Previous work has demonstrated that the sensitization of spinal neurons and microglia is important in the development of pain behaviors induced by BmK I, a Na channel activator and a major peptide component of the venom of the scorpion Buthus martensi Karsch (BmK). We found that the expression of P2X7 receptors (P2X7Rs) was up-regulated in the ipsilateral spinal dorsal horn after BmK I injection in rats. P2X7R was selectively localized in microglia but not astrocytes or neurons. Similarly, interleukin 1β (IL-1β) was selectively up-regulated in microglia in the spinal dorsal horn after BmK I injection. Intrathecal injection of P2X7R antagonists largely reduced BmK I-induced spontaneous and evoked pain behaviors, and the up-regulation of P2X7R and IL-1β in the spinal cord. These data suggested that the up-regulation of P2X7Rs mediates microglial activation in the spinal dorsal horn, and therefore contributes to the development of BmK I-induced pain.

Low-Frequency Electroacupuncture Alleviates Chronic Constrictive Injury-Induced Mechanical Allodynia by Inhibiting NR2B Upregulation in Ipsilateral Spinal Dorsal Horn in Rats / 中国结合医学杂志

OBJECTIVE@#To study the effects of electroacupuncture (EA) in chronic constrictive injury (CCI) rat model and the expression of N-methyl-D-aspartate receptor type 2B (NR2B) in ipsilateral spinal dorsal horn in rats to explore the analgesic mechanisms of EA.@*METHODS@#According to the random number table, totally 180 rats were evenly divided into a sham group, a CCI group, and an EA group. CCI model was conducted with four 4-0 chromic gut ligatures loosely ligated around the left sciatic nerve 1 cm above the trifurcation. Rats in the EA group received 2 Hz EA therapy bilaterally at acupoints of Zusanli (ST 36) and Sanyinjiao (SP 6) once daily (30 min/d) for 30 days after surgery. Paw withdrawal thresholds (PWTs) were measured on 0 (baseline), 1, 3, 7, 15, 30 days after surgery. Rats were sacrificed on 0, 1, 3, 7, 15 and 30 days after surgery, and the L4-5 segments of spinal cord were removed to detect the expression of NR2B by immunohistochemistry and quantitative polymerase chain reaction.@*RESULTS@#PWTs in the CCI group were significantly lower than the sham group at Day 1-30 after surgery, and reached its lowest at Day 1 (P<0.01). After EA treatment, the PWTs recovered rapidly and were significantly higher than those in the CCI group on 3, 7, 15 and 30 days after surgery (P<0.01). The numbers of NR2B-immunoreactive cells of the CCI group significantly increased after CCI surgery compared with the sham group (P<0.01). Compared with the CCI group, stimulation of EA markedly decreased the numbers of NR2B-immunoreactive cells at Day 3, 7, 15 and 30 (P<0.05). In the sham group, NR2B mRNA was expressed at a low level. It increased after CCI surgery, which increased rapidly at Day 7 (P<0.01) and reached its peak value at Day 15 (P<0.01). After EA stimulation, relative quantity of NR2B mRNA expression was less than that in the CCI group at Day 15 and 30 (P<0.05).@*CONCLUSIONS@#Low frequency of EA had antinociceptive effect in CCI rat model. The analgesic effects of EA might be through the inhibition of NR2B.

Effect of sciatic nerve pulsed radiofrequency glial activation levels in spinal dorsal horn in chronic constriction injury rat models and its analgesia effect / 吉林大学学报(医学版)

Objective:To observe the effect of sciatic nerve pulsed radiofrequency (PRF) on the activation levels of microglia cells and astrocytes in spinal dorsal horn in the chronic constriction injury (CCI) rat models, and to explore the relationships between the analgesic mechanism of sciatic nerve PRF and the activation levels of microglia cells and astrocytes in the spinal dorsal horn.Methods:Forty male SD rats were randomly divided into CCI shamoperation+RPF sham group (SS group) , CCI sham-operation+RPF group (SP group) , CCI+RPF sham group (CS group) , CCI+RPF group (CP group) (n=10) .PRF was applied on the sciatic nerve on the 4th day after CCI operation for 120s, with a maximum temperature of 42℃.The mechanical withdrawal thresholds (MWT) and thermal paw withdrawal latencies (TWL) were measured to evaluate mechanical hyperalgesia and thermal hyperalgesia 1dbefore operation (D0) and 1, 3, 5, 7dafter operation (D1, D3, D5, D7) .Western blotting method was used to detect the protein expression levels of ionized calcium binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) in the ipsilateral spinal dorsal horn of L3-5after pain behavioral test (D7) .Results:Compared with SS group, the rats in CS group after CCI had the significant behavioral changes, such as hallux valgus, lameness, toe bending, and foot raising during walking;MWT and TWL were decreased significantly (P＜0.01) ;the expression levels of Iba-1and GFAP proteins in the ipsilateral spinal dorsal horn were increased significantly (P＜0.05) .Compared with CS group, the behavioral changes of the rats in CP group (D5, D7) such as hallux valgus, lameness, toe bending, and foot raising during walking were alleviated significantly;MWT and TWL were increased significantly (P＜0.01) ;the Iba-1protein expression level in spinal dorsal horn was downregulated significantly (P＜0.05) and the GFAP protein expression level did not change significantly (P＞0.05) .Conclusion:PRF on sciatic nerve can relieve the neuropathic pain (NP) of the CCI rat models;PRF on sciatic nerve can inhibit activation of the microglia cells in the spinal dorsal horn.The analgesic mechanism of PRF on sciatic nerve may be associated with the inhibition of the activation of microglia cells in the spinal dorsal horn.

Effect of osthole on p38 MAPK signaling related pathway of rat model with inflammatory radicular pain induce by nucleus pulposus in the spinal horn / 中国药理学通报

Aim To observe the effect of epidurally application of osthole on the model of nucleus pulposusinduced inflammatory radicular pain and the expression of p38 MAPK signaling related pathway in the spinal dorsal horn of rats.Methods The model of radicular pain was generated by putting nucleus pulposus to the L5 dorsal root ganglion (DRG).50％ MWT was measured using Von Frey filaments to calculate mechanical pain threshold before and after operation.50 μL of 20 g · L-1 osthole was administered epidurally in group Ost and 50 μL of 100 mL · L-1 DMSO in group DMSO at postoperative day (POD).The expression of phosphorylated p38 (p-p38),IL-18 and IL-18R in the lumbar spinal dorsal horn was detected by Western blot.IL-18 mRNA was assessed by real-time PCR.Results The mechanical pain threshold significantly decreased after operation (P ＜ 0.05),while the expression of protein p-p38 MAPK,IL-18,IL-18R and IL-18 mRNA was significantly different.Compared with DMSO group,50％ MWT was significantly increased and accompanied with the decrease of protein p-p38,IL-18,IL-lgR and IL-18 mRNA in Ost group after drug administration (P ＜ 0.05).The correlation analysis between protein concentration of p38 MAPK and IL-18 mRNA showed that the Spearman correlation coefficient was 0.9 (P ＜ 0.05).Conclusion p-p38 and IL-18 of spinal dorsal horn participate in the rat model with inflammatory radicular pain induced by nucleus pulposus,and IL-18R plays a role in maintenance of the pain.Osthole administered epidurally in the early stage of pain could alleviate the pain for a long time,which may be related with inhibiting p38 MAPK signaling related pathways.

Effects of intrathecal injection Roscovitine on the pain behavior and the expression of ERK1/2 and PPARγ protein in spinal cord in rats with neuropathic pain / 中华行为医学与脑科学杂志

Objective To investigate the effects of intrathecal injection of Roscovitine on the pain behavior and the expression of pERK1/2 and pPPARγ receptor in spinal cord in rats with neuropathic pain.Methods Fifty-two male adult Sprague-Dawley rats of 220～ 250 g were randomly divided into 4 groups:Sham+DMSO group (dimethyl sulfoxide,S+D group),Sham+Roscovitine (S+R) group,CCI+ DMSO group (I+D),CCI+ Roscovitine (I+R) group.The corresponding drugs were administered by intrathecal injection from the seventh day after CCI once a day for 14 days.The right hind paw mechanical threshold value (PMWT) was measured by Von Frey filament and paw thermal withdrawal latency(PWTL) was measured by Hargreaves methods before 1 day and 3 d,7 d,10 d,14 d after surgery.The spinal cord lumbar enlargement was taken at 14 d after surgery,and Cdk5,p35,phosphorylated ERK protein (pERK),total ERK protein (ERK),phosphorylated PPARγprotein (pPPARγ) and total PPARγ protein (PPARγ) were detecteded by Western blot.Results Roscovitine was administered by intrathecal injection alleviated mechanical allodynia and thermal hyperalgesia of CCI rats.Compared with I+D group,PWMT in I+R group at 7 d,10 d,14 d after administration((4.65±0.08)g,(6.47±0.12)g,(7.90±0.19)g,) vs ((3.71 ±0.06)g,(2.45±0.17)g,(2.31±0.15)g) (Fgroup =505.71,P＜0.05,Ftime×group =15.33,P＜0.05),PWTL((9.22±0.33) s,(13.52±0.43) s,(12.63±0.88) s) vs ((8.02±0.20) s,(5.90±0.28) s,(5.40±0.38) s) (Fgroup =355,P＜0.05,F time×group =8.589,P＜0.05) were significantly increased.Compared with I+D group(p35 (0.58±0.02),pERK (1.12±0.13),pPPARγ (0.77±0.16)),p35 (0.46±0.04,F=11.06,P＜0.05) and pERK(0.79±0.11,F =22.91,P＜ 0.05) in I+ R group,were significantly dereased,and the expression of pPPARγ(0.99±0.13,F =17.62,P＜0.05))was significantly increased.Conclusion Intrathecal injection Roscovitine can alleviate both mechanical allodynia and thermal hyperalgesia in rats with neuropathic pain,and its mechanisms may be related to the inhibition of Cdk5/p35 and ERK activity,enhancement of PPARγ activity in the spinal dorsal horn.

Modulation of Pain and Itch by Spinal Glia / 神经科学通报·英文版

Chronic pain and itch are a pathological operation of the somatosensory system at the levels of primary sensory neurons, spinal cord and brain. Pain and itch are clearly distinct sensations, and recent studies have revealed the separate neuronal pathways that are involved in each sensation. However, the mechanisms by which these sensations turn into a pathological chronic state are poorly understood. A proposed mechanism underlying chronic pain and itch involves abnormal excitability in dorsal horn neurons in the spinal cord. Furthermore, an increasing body of evidence from models of chronic pain and itch has indicated that synaptic hyperexcitability in the spinal dorsal horn might not be a consequence simply of changes in neurons, but rather of multiple alterations in glial cells. Thus, understanding the key roles of glial cells may provide us with exciting insights into the mechanisms of chronicity of pain and itch, and lead to new targets for treating chronic pain and itch.

Involvement of NF-κB and the CX3CR1 Signaling Network in Mechanical Allodynia Induced by Tetanic Sciatic Stimulation / 神经科学通报·英文版

Tetanic stimulation of the sciatic nerve (TSS) triggers long-term potentiation in the dorsal horn of the spinal cord and long-lasting pain hypersensitivity. CX3CL1-CX3CR1 signaling is an important pathway in neuronal-microglial activation. Nuclear factor κB (NF-κB) is a key signal transduction molecule that regulates neuroinflammation and neuropathic pain. Here, we set out to determine whether and how NF-κB and CX3CR1 are involved in the mechanism underlying the pathological changes induced by TSS. After unilateral TSS, significant bilateral mechanical allodynia was induced, as assessed by the von Frey test. The expression of phosphorylated NF-κB (pNF-κB) and CX3CR1 was significantly up-regulated in the bilateral dorsal horn. Immunofluorescence staining demonstrated that pNF-κB and NeuN co-existed, implying that the NF-κB pathway is predominantly activated in neurons following TSS. Administration of either the NF-κB inhibitor ammonium pyrrolidine dithiocarbamate or a CX3CR1-neutralizing antibody blocked the development and maintenance of neuropathic pain. In addition, blockade of NF-κB down-regulated the expression of CX3CL1-CX3CR1 signaling, and conversely the CX3CR1-neutralizing antibody also down-regulated pNF-κB. These findings suggest an involvement of NF-κB and the CX3CR1 signaling network in the development and maintenance of TSS-induced mechanical allodynia. Our work suggests the potential clinical application of NF-κB inhibitors or CX3CR1-neutralizing antibodies in treating pathological pain.

Allopregnanolone suppresses mechanical allodynia and internalization of neurokinin-1 receptors at the spinal dorsal horn in a rat postoperative pain model

BACKGROUND: To identify a new strategy for postoperative pain management, we investigated the analgesic effects of allopregnanolone (Allo) in an incisional pain model, and also assessed its effects on the activities of the primary afferent fibers at the dorsal horn. METHODS: In experiment 1, 45 rats were assigned to Control, Allo small-dose (0.16 mg/kg), and Allo large-dose (1.6 mg/kg) groups (n = 15 in each). The weight bearing and mechanical withdrawal thresholds of the hind limb were measured before and at 2, 24, 48, and 168 h after Brennan's surgery. In experiment 2, 16 rats were assigned to Control and Allo (0.16 mg/kg) groups (n = 8 in each). The degree of spontaneous pain was measured using the grimace scale after the surgery. Activities of the primary afferent fibers in the spinal cord (L6) were evaluated using immunohistochemical staining. RESULTS: In experiment 1, the withdrawal threshold of the Allo small-dose group was significantly higher than that of the Control group at 2 h after surgery. Intergroup differences in weight bearing were not significant. In experiment 2, intergroup differences in the grimace scale scores were not significant. Substance P release in the Allo (0.16 mg/kg) group was significantly lower than that in the Control group. CONCLUSIONS: Systemic administration of Allo inhibited mechanical allodynia and activities of the primary afferent fibers at the dorsal horn in a rat postoperative pain model. Allo was proposed as a candidate for postoperative pain management.